Preparation And Microstructure Research Of Metaland Magnetic Alloy Arrays

As electronic information science and technology development, one-dimensionalnanometerials have attracted increasing attention due to their novel optical, electronic, magneticand chemical properties. In this work, Pt, Fe, Co and Fe-Co, Sm-Co alloy nanowires wereformed in the pores of porous anodic aluminum oxide template (AAO) by dc electrochemicaldeposition. The morphology, structure and magnetic properties of the nanowires were studied byfield emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) and vibratingsample magnetometer (VSM). And the influence of heat treatment on the structure and magneticproperties of the Fe-Co, Sm-Co alloy nanowires were also studied. This thesis presents thefollowing work:1. AAO templates with different pores were prepared by two-step anodization method insulphuric acid, oxalic acid and phosphoric acid respectively. The morphology of AAO wasinvestigated by field emission scanning electron microscope (FE-SEM). The affecting factorsinvolved in the templates were concluded from votage, the kind of electrolytes and reaming time.At last, the suitable processing conditions have been obtained to prepare high quality AAOtemplates and the formation mechanism of AAO was also discussed.2. The nanowire arrays were observed by FE-SEM.The Photos showed that the nanowirearrays had a good linear structure, the same diameters, large aspect ratio and the diameter of thenanowires is equal to the pore size of the template. Direct voltage electrodeposion was appliedfor the first time to fabiricate Pt nanowire arrays within the pores of AAO templates. The XRDresults showed Pt nanowires have fcc polycrystalline structure with (111) preferred orientation.Fe, Co, Fe₃Co₇ and Fe₇Co₃ alloy nanowire arrays show clearly magnetic anisotropy, easymagnetization direction is along nanowires'long axis direction. This is mainly due to shapeanisotropy.3. The ordered Sm-Co alloy nanowires were electrodeposited in the AAO templates by dc electrochemical deposition. The wires Proved to be amorphous structure by the XRD technology.While after heat treatment, they would be turned into SmCo₅ and Co nanowires. The TEMobservations indicated that the Sm-Co alloy nanowires had the same good linear structure, thediameter of the wires were about 40 nm. The Energy Dispersive Spectroscopy (EDS) analysisdisPlayed: The rare earth element Sm was induced by the transitional metal Co, and theyco-deposited from the aqueous solution together.